Cup-shaped housing and condenser with said housing

ABSTRACT

A housing ( 1 ) having a lid ( 5 ), for electrochemical cells having at least two electrodes is proposed, wherein indentations ( 5 B,  10 B) for contacting the electrodes are present both in the lid and in the housing bottom. In this arrangement, the indentations demonstrate a cross-section that narrows into the interior of the housing, so that a particularly large, easily welded contact area between the indentations and the electrodes is the result.

Electrodes of electrochemical cells, such as capacitors or batteries,are frequently accommodated in cup-shaped housings. These housings aredelimited by a bottom on one side and closed off with a lid on the otherside. On the lid, there are generally two electrical connectors thatserve for contacting the electrodes located in the interior of thecup-shaped housing. In this arrangement, conductors made of electricallyconductive material are frequently either affixed to the electrodes, orprojecting regions of the electrodes are trimmed in such a manner thatprojecting conductors are formed. These conductors are then connectedwith the electrical connectors either by means of screw connections (seeFIG. 1A) or connected rigidly by means of welding. Such contact betweenthe electrodes and the electrical connectors is difficult to implementand, therefore, very time-consuming and thus also costly in production.

In another variant of cup-shaped housings for electrochemical cells, theelectrodes are contacted via indentations having a rectangularcross-section, which are, for example, arranged on the inside walls ofthe lid and the housing bottom. In this case, the potential of the oneelectrode is applied to the housing cup, which must be insulatedelectrically from the lid, which has the potential of the otherelectrode applied to it. As is evident in FIGS. 2A and 2B, theseindentations contact projecting regions of the electrodes, whereby as arule only a small contacting area is present between the indentationsand the electrodes. Such contact points are furthermore also frequentlywelded using a laser, for example. Since the laser beam is frequentlycone-shaped in the region of the indentation, it is weakened at theouter edges of the indentation in the case of rectangular indentationsso a very low input of energy of the laser into the interior of theindentation results, so that the indentation might be onlyinsufficiently welded to the electrode (see FIG. 2B, for example).

In this arrangement, in the case of capacitors and batteries, porousseparators are frequently present between the two electrodes withdifferent polarities, which separators are saturated with an electrolytesolution so that the two electrodes are in contact with the electrolytesolution.

Frequently, in the case of conventional housings, electricalinsulations, e.g., plastic injection-molded parts, are present betweenthe housing and the lid (see FIG. 1A, for example) if differentpotentials are applied to the lid and the housing. Furthermore, sealingrings are also present in this arrangement, which form a tight sealbetween the housing and the lid so that the electrolyte solution cannotget into the environment. Such embodiments require an accordingly longand therefore cost-intensive assembly because of their complicatedstructure.

It is therefore the task of the present invention to provide acup-shaped housing for electrochemical cells that allows particularlysimple contacting between the electrodes and the lid as well as thehousing.

This task is accomplished via a housing according to claim 1.Advantageous embodiments of the housing are the object of dependentclaims.

The invention provides a cup-shaped housing for electrochemical cellshaving at least two electrodes, wherein the cup-shaped housing has a lidin which a first indentation, directed inwards, for contacting a firstelectrode, is formed, and in which a second indentation, directedinwards, for contacting a second electrode, is formed in the housingbottom. In this arrangement, the first and the second indentation have across-section that narrows into the interior of the housing.

The advantage of a housing according to the invention is that because ofthe narrowing cross-section of the first and second indentation, a muchlarger contact area between the indentation and the electrodes than inthe case of conventional housings is the result. Furthermore, via thisspecial shape of the indentation, a maximal non-positive lock betweenthe indentation and the electrodes is achieved. Because thecross-section of the indentations narrows into the interior of thehousing, it is furthermore easily possible to allow a high input ofenergy into the indentation in the case that the contact point is weldedvia a laser beam, for example, so that the electrodes are meltedtogether with the indentations particularly well (see also FIG. 3B, forexample).

In an advantageous embodiment of the housing, the first and the secondindentation extend in a straight line over a large portion of an expansedirection of the lid and of the housing bottom. A housing structured insuch a manner has the advantage that via the spatial expanse of theindentation, a particularly large contact area between the indentationsand the electrodes is created.

In another variant of the housing according to the invention, the firstand the second indentation are each formed by a separate componentaffixed to the inside of the lid or to the inside of the housing bottom,respectively. This can be done via welding or riveting, for example.

The material of housings according to the invention can comprise, forexample, a number of aluminum alloys, for example aluminum 99.5 oraluminum 99.9, as well as aluminum forging alloys. The advantage ofthese materials is that they have good electrical conductivity, for onething, so that the potential of the electrodes can be applied to themwell, and that for another thing, they demonstrate good deformationproperties, so they can be worked easily, hot or cold, for example viaextrusion. In the case of housings according to the invention, made ofthis material, it is possible, for example, to form the first and secondindentation via extrusion. In this manner, the indentations canadvantageously be formed in one step with the housing and with the lid.

In another advantageous embodiment of a housing according to theinvention, an electrically insulating component made in one piece ispresent that runs circumferentially around the lid and is arranged in asealed manner between the lid and the wall of the housing (see FIG. 4A).Via this electrically insulating component, housings according to theinvention can be sealed in a particularly simple manner, and, at thesame time, the lid can be insulated electrically from the housing. Thustwo functions (seal and electrical insulation) are integrated in asingle component, in a particularly advantageous manner.

In contrast to conventional seals and insulations, which consist of twocomponents, a particularly simple assembly of a housing according to theinvention can be guaranteed by the one-piece electrically insulatingcomponent according to the invention, in the region of the lid.

In another embodiment, first regions of the electrically insulatingcomponent are arranged circumferentially around the lid, outside of thehousing interior, whereby they have a notch into which the edge of thehousing, towards the housing interior, is turned over circumferentially.In this arrangement, these regions with the notch allow particularlysimple flanging of the housing and therefore a particularly reliableseal.

In this arrangement, the electrically insulating component can compriserubber, e.g., acryl/nitrile/butadiene rubber.

In another embodiment, the invention describes an electrochemical cellthat is a capacitor and, in this arrangement, has a cup-shaped housingaccording to the invention. A layer stack that comprises the first andthe second electrode, formed as electrode layers in this case, isaccommodated in the interior of the housing. Under some circumstances, aflat separator saturated with an electrolyte solution can be locatedbetween the electrode layers. The faces of the layer stack lie oppositethe lid and the housing bottom, respectively (see FIG. 3A, for example).At the faces of the layer stack, edge regions of either the first or thesecond electrode layer, respectively, project and are turned over at thecontact points with the indentations to increase the contact area. Thismeans that regions of the first electrode layer project out of the topface of the layer stack, for example, and regions of the secondelectrode stack project out of the face that lies opposite the housingbottom (see FIG. 3A). The indentation located on the inside of the lidthen contacts the projecting regions of the first electrode layer sothat the potential of the first electrode layer is applied to the lid.The indentation formed in the housing bottom then contacts theprojecting regions of the second electrode layer so that the potentialof the second electrode layer is applied to the housing cup.

It is advantageous if the contact points between the indentations andthe electrode layers are welded. In this case, a particularly intimatecontact between the indentations and the electrode layers is the result.In this arrangement, the contact layers can be laser-welded. Because ofthe particular cross-sectional shape of the indentations, which narrowsinto the interior of the housing, a particularly high input of energycan be transferred at the weld points by laser beam so that particularlygood welding can take place using a laser beam. The layer stackdescribed here can also be rolled up to form a capacitor winding in thisarrangement.

In the following, the invention will be explained in greater detail,using exemplary embodiments and figures.

FIG. 1A shows a conventional capacitor that contains a layer stack thatcomprises electrode layers.

FIG. 1B shows a conventional capacitor winding that can be accommodatedin a housing.

FIGS. 2A and 2B show a conventional capacitor with indentations thathave a rectangular cross-section, in cross-section and in detail.

FIGS. 3A and 3B show a capacitor with a housing according to theinvention, in cross-section and in detail.

FIGS. 4A and 4B show a capacitor with another variant of a housingaccording to the invention, in cross-section and in a top view.

FIG. 1A shows a capacitor with a conventional housing. In the capacitorhousing 1, there is a layer stack that consists of a first electrodelayer 16, a second electrode layer 17, and a separator 14 locatedbetween them. The separator is usually impregnated with an electrolytesolution. On the lid 5 of the housing 1, there are electrical connectors25, which contact the first and second electrode layer, respectively, byway of conductors 50, which are attached to the electrode layers. Suchcontacting of the electrical connectors with the electrode layers canonly be implemented with a great deal of effort, as already describedabove.

Instead of the layer stack shown in FIG. 1A, a capacitor winding canalso be introduced into the housing. In this arrangement, a firstelectrode layer 16, a separator 14, as well as a second electrode layer17, are wound up around a core tube or around a mandrel, which leavesthe hole 20 when it is removed. In this embodiment of the capacitor aswell, the electrode layers, in each instance, can be contacted by way ofprojecting conductors 50.

FIG. 2A shows another embodiment of a capacitor having a conventionalhousing. It can be seen that a capacitor winding 15 is introduced intothe housing 1, whereby the hole 20 that remains after removal of thecore tube or the mandrel is located in the center of the capacitorwinding 15. The lid 5 with the electrical connector 25 has anindentation 5 a that is directed inwards and is rectangular incross-section and contacts the projecting regions 16 a of the secondelectrode layer 16. The capacitor lid therefore has the potential of thefirst electrode layer applied to it. In the housing bottom, there is asecond indentation 10 a, which is also rectangular in cross-section,whereby the latter contacts the projecting regions 17 a of the secondelectrode layer 17. The housing cup therefore has the potential of thesecond electrode layer applied to it. For electrical insulation, anelectrical insulation 6 is located between the housing cup and the lid.Furthermore, a sealing ring 7 is present. In FIG. 2B, the circledesignated as 11 in FIG. 2 a can be seen on a larger scale. It isevident that the second indentation 10 a, in this case, has only a verysmall contact area 17C with the projecting regions 17A of the secondelectrode layer 17, because of the rectangular cross-section.Furthermore, the cone 30 of a laser beam is shown schematically. It isclearly evident that the outer edges 10B of the indentation 10A projectinto the laser cone 30 and thereby reduce the energy input of the laserinto the indentation. Because of this reduction in energy input, theconnection between the indentation 10A and the contact area 17C with theprojecting regions 17A of the second electrode layer is not so goodduring welding.

FIG. 3A shows a capacitor having a housing according to the invention.Both in the lid 5 and in the bottom of the cup there are indentations 5Band 10B, respectively, which are directed inwards. Both indentationshave a cross-section that narrows towards the inside. In FIG. 3B, thecircle designated as 12 in FIG. 3A is shown on a larger scale. It can beseen that because of the narrowing cross-section of the indentation 10B,particularly large contact areas 17D between the indentation and theprojecting regions 17A of the second electrode layer 17 are the result.In this arrangement, the projecting regions of the electrode layers canbe turned over at the contact point in such a manner that possibly twoor more electrode layers lie on top of one another and are compressed sothat particularly good contact between the indentation and the electrodelayer is the result. Furthermore, it is clearly evident that acone-shaped laser beam 30 that is shown schematically here is notweakened by the edges of the indentation, so that a particularly goodenergy input of the laser beam becomes possible and therefore aparticularly good weld between the indentation and the contact points17D with the projecting regions of the electrode layer is possible.

FIG. 4A shows a capacitor with another variant of a housing according tothe invention. It can be seen that in this case, the indentations bothin the lid and in the cup bottom are formed to be elongated. Because ofthis special shape of the indentations, a particularly large contactarea between the indentations and the electrode layers is the result.Furthermore, an electrically insulating component 21 is present. Thiscomponent 21 is arranged between the lid 5 and the wall of the housing1, in sealed manner, and thereby at the same time insulates the lidelectrically from the housing, and seals the housing. First regions 21 Aof the electrically insulating component are arranged outside thehousing interior, circumferentially around the lid, and have a notch 21Cinto which the edge of the housing is turned over. Therefore it ispossible to implement particularly easy flanging by means of theelectrically insulating component 21. Furthermore, second regions 21B ofthe electrically insulating component are present in the interior of thehousing, which regions are arranged between the wall of the housing andthe projecting edge regions 16A of the first electrode layer. Theseregions 21B insulate the projecting edge regions of the electrode fromthe housing in a particularly simple manner. A circumferentialindentation 26 in the form of a bead is formed in the wall of thehousing, which bead in addition fixes the electrically insulatingcomponent 21 in place.

In FIG. 4B, the lid of the housing shown in FIG. 4A can be seen in a topview. It is evident that six indentations 5B, arranged in star shape,are present in the housing lid, which indentations can produce aparticularly intimate contact with the electrode layer. Furthermore, oneor more electrical connectors 25 are formed on the housing.

The invention is not limited to the exemplary embodiments shown here.Other variations are possible, both with regard to the number ofindentations in the housing and with regard to their form. Theelectrodes that are contacted by means of the indentations can also beconfigured differently. Thus, for example, not only the layer stacksshown but also windings or electrodes configured in another manner arepossible.

1. A housing for an electrochemical cell having at least a firstelectrode and a second electrode the housing comprising: a lid having afirst indentation to contact the first electrode; and a bottom having asecond indentation to contact the second electrodes; wherein the firstindentation has a first cross-section and the second indentation has asecond cross-section, the first cross-section and the secondcross-section getting narrower as the first indentation and the secondindentation progress into an interior of the housing.
 2. The housing ofclaim 1, wherein the first indentation and the second indentation extendin substantially a straight line over the lid and the bottom,respectively.
 3. The housing of claim 1, wherein the bottom and the lidare part of separate components.
 4. The housing of claim 1, wherein ofthe housing comprises aluminum or aluminum forging alloys.
 5. Thehousing of claim 1, further comprising: an electrically insulatingcomponent that is at least partly around an edge of the lid and that isbetween the lid and a wall of the housing.
 6. The housing of claim 5,wherein first regions of the electrically insulating component arearranged around a circumference of the lid and outside of an interior ofthe housing, the first regions having a notch; and, wherein an edge ofthe housing is turned towards the housing an interior, of the housingaround the lid such that the turned edge is within the notch.
 7. Thehousing of claim 5, wherein the electrically insulating componentcomprises rubber.
 8. A capacitor comprising: a housing comprising: a lidhaving a first indentation, the first indentation having a firstcross-section that gets narrower inside the housing; and a bottom havinga second indentation, the second indentation having a secondcross-section that gets narrower inside the housing; and a layer stackthat comprises a first electrode layer and a second electrode layer, thelayer stack having faces that are substantially opposite the lid and thebottom; wherein an edge of at least one of the first electrode layer andthe second electrode layer extends out of a face of the layer stack andis bent at contact points with at least one of the first and secondindentations.
 9. A capacitor comprising: a housing comprising: a lidhaving a first indentation, the first indentation having a firstcross-section that gets narrower inside the housing, a bottom having asecond indentation, the second indentation having a second cross-sectionthat gets narrower inside the housing; and an electrically insulatingcomponent that is around the lid; a layer stack comprising alternatingelectrode layers including a first electrode layer and a secondelectrode layer the layer stack being disposed inside the housing suchthat faces of the layer stack formed by outer edges of the electrodelayers are substantially opposite the lid and the bottom; wherein anedge of at least one of the first electrode layer and the secondelectrode layer extends out of a face of the layer stack and is bent atcontact points with at least one of the first and second indentations;and wherein regions of the electrically insulating component are insidethe housing between a wall of the housing and a bent edge of the firstelectrode layer or the second electrode layer.
 10. The capacitor ofclaim 9 wherein contact points between at least one of the first andsecond indentations the alternating electrode layers are welded.
 11. Thecapacitor of claim 10 wherein the contact points are laser-welded. 12.The capacitor of claim 9 wherein the layer stack is rolled to produce acapacitor winding.
 13. The capacitor of claim 9, wherein second regionsof the electrically insulating component are arranged around acircumference of the lid and outside of an interior of the housing, thefirst regions having a notch; and wherein an edge of the housing isturned towards an interior of the housing around the lid such that theedge is within the notch.
 14. The capacitor of claim 9, wherein theelectrically insulating component comprises rubber.
 15. The capacitor ofclaim 9, wherein the first indentation and the second indentation extendin substantially a straight line over the lid and the bottom,respectively.
 16. The capacitor of claim 9, wherein the bottom and thelid are part of separate components.
 17. The capacitor of claim 9,wherein the housing comprises aluminum or aluminum forging alloys. 18.The capacitor of claim 8, wherein contact points between at least one ofthe first and second indentations and a corresponding electrode layerare welded.
 19. The capacitor of claim 8, wherein the layer stack isrolled to produce a capacitor winding.
 20. The capacitor of claim 8,wherein the housing further comprises: an electrically insulatingcomponent that is at least partly around an edge of the lid.